package-lock.json migration from npm v6 to v7+ lockfileVersion 2

Updating a project from npm v6 to npm v7 or later triggers an automatic migration of the package-lock.json file to lockfileVersion: 2. This version change is designed to support new features like native workspaces and improved dependency resolution.

The primary constraint is maintaining environment parity across development machines and legacy CI/CD pipelines that may still rely on npm v6. Because lockfileVersion 2 is not backward compatible, a commit containing the updated lockfile will cause installation failures or unexpected dependency tree mutations on older npm versions.

• Is there a configuration setting to prevent the automatic upgrade of the lockfile version during npm install in v7+?
• What is the recommended strategy for projects that must support both npm v6 and v7+ concurrently without mutating the lockfile?